My mother-in-law gave this to us last week, and this is the first time I’ve ever seen one. The flavor is 90% lemon and 10% pomelo (grapefruity), which is surprising since it looks mostly like a pomelo. This probably means it can be used as a lemon substitute for many cooking applications , and in fact, Nam put it in a killer Tom Kha Gai last night. The pomelo flavor was not noticeable at all. Overall though, it wasn’t quite as sour or pure as a normal Thai lemon – the flavor was a bit muddled.
In the first pic, I included a few objects for size reference: A small bottle of Sriracha, an Old Spice deodorant stick, and a tube of CPU grease. You know, random things I use every day, strewn all over the kitchen counter.